The invention discloses a wind energy/wave energy integrated power generation device and a power generation method thereof. The wind energy/wave energy integrated power generation device comprises a hollow pile; the bottom of the hollow pile is inserted into the bottom of the sea, and the top of the hollow pile extends out of the surface of the sea; wind driven generator blades are installed on the top of a tower; electricity generated by a wind driven generator is transmitted to a controller in the tower; the controller supplies power to various components in the wind driven generator; the controller is also electrically connected with an external grid through a cable; the hollow pile is sleeved with a water storage pool; the top of the water storage pool is located above the surface of the sea; a rising slope is arranged between the surface of the sea and the top of the water storage pool; the bottom of the water storage pool is below the surface of the sea; a descending slope is arranged between the surface of the sea and the bottom of the water storage pool; the rising slope and the descending slope are in butt joint with each other so as to form an ice-resisting cone; the upper part of the water storage pool is open; two or more water-discharging holes are formed in the bottom of the water storage pool; and water turbines are installed in the water-discharging holes respectively. According to the power generation device of the invention, a relatively mature offshore wind power technology and a wave energy power generation technology with a great development potential are combined together so as to form a complementary power generation system, and therefore, grid-connected power generation can be realized with high possibility; offshore wind energy foundation pilesare effectively utilized; and a wave energy generation device and a wind energy power generation device share one set of power transmission system, and therefore, the power generation cost of the waveenergy power generation device can be decreased.